Cylinder liner for opposed piston engines



June 29, 1948. H. STEINER 2,444,382

CYLINDER LINER F OR QPPQSED PISTON ENGINES Filed Aug. 9, 1945 I 22 v! P 'f\ I x /l l 3; I

5L I 6 g i l W L N 1' I k Z5 26 INVENTOR HANS GTE/NEE ATTORNEYS Patented June 29, 1948 UNITEDJSTAT ESP-AT CYLINDER LINER FOR OPPOSED I ENGINES em" OFFICE' -Hans Steiner, Winterthur, Switzerland, assignor to Sulzer Freres, Societ Switzerland e Anonyme, Wint'erthur,

Application August 9, 1945, Serial No. 609,859, i In Switzerland September 26, 1944 1 f This invention relates to a cylinder liner for internal combustion engines with opposed pistons, the middle part of the liner being cooled by a cooling-medium introduced through passages,

- i and consists in that the inner surface of the cylinderllner deviatesifrom the cylindrical shape in inder-wall temperatures, lower lubricating oil consumption and less thermal stresses.

Three embodiments of the invention are shown diagrammatically in the accompanying drawings, in which; i

Fig. l is a longitudinal section through the cylinder liner of an opposed-piston internal combustion engine;

Fig. 2 illustrates, on a larger scale, the middle part of the liner shown in Fig. 1; and

Figs. 3 and 4 illustrate modified shapes of the middle part of the cylinder liner.

' In Fig. 1 the two pistons 2 and 3 in the cylinder liner I are shown at the irmer dead centre. The scavenging, or charging and supercharging air,

enters the'cylinder through the scavenging ports 4. The exhaust gases leave the cylinder through the exhaust ports 5. In the strengthened middle part 6, the cooling-medium is led through passages 29 which run obliquely to the cylinder axis 20, the axesof the passages 29 belonging to the generating lines of a hyperboloid of revolution of one sheet whose axis of revolution is the cylinder axis 20 and whose fundamental circle lies in the middle plane 2| through the cylinder. Consequently in the plane 2| the distance of the passages 29 from the cylinder axis 20 is the smallest.

In contrast to known constructions, the inner diameter of the cylinder liner I at its central portion 22, not swept by the piston rings 30, deviates from the cylindrical shape in that it diminishes as the middle sectional plane 2| is approached in such a way that its inner surface conforms to the run of the cooling passages 29 to provide at least a constant wall thickness in that inner surface and those cooling passages. The inner surface of the liner I thus adopts in the zone 22 at least approximately the form of a hyperboloid revolution with the cylinder axis 20 as axis of revolution. Therefore, although the cooling passages 29 come nearest to the cylinder axis 20 in the middle sectional plane 2 I, their distance from the inner surface of the liner remains small in the zone in which the piston rings 30 lie at inner .6 Claims. (of. 123-173 dead center. Because of this special form of inner surface of the liner I, it is possible, as shown in Fig. 1, to make a satisfactoryfcylinder liner with only oneseries of bores 29 made from one side of the strengthened middle part 6 straight through to thebther, and, nevertheless to have a sufiicient distance separatin them from the inner surface of the cylinder liner inthe neighthe wall. must be so shaped that they do not knock against borhood of its middle sectional plane 2| to provide the desired distribution of temperature in Naturally the crowns of the pistons the wall of .the cylinder lineril inthe reduced face ofrotation which contains'the centerlines of all the cooling passage 29! The internal diameter of the cylinder liner diminishes from A and 3 toward themiddle sectional plane 2|of the cylinder, as explained in the above, "in connection with Fig. 1. Correspondingly, the diameter of thepiston crown' 21 and 28 is smaller than the diameter of the piston barrels. Thus, the wall thickness between the cooling passages and inner surface of the liner may even increase toward the middle sectional plane of the cylinder, thus causing a higher wall temperature in zone 22 not swept by the piston rings without any attendant danger. On the other hand, if the engine is subjected to high thermal stresses, it may be advisable to allow the wall thickness between the gasheated surface and the passages to decrease towards the middle of the cylinder, in order that this zone, where heat exchange is greatest, may be relieved from heat stresses as much as possible. By a suitable choice of the run of the diameter between A and B, and further by suitable arranging of the cooling-passages, the course taken by the cylinder wall temperature can be efiectively influenced.

In the embodiment shown in Fig. 3 the cooling-medium passages also run obliquely to the cylinder axis. The sectional plane on which this figure is taken produces the ellipses |2, |9, ll, l5, l6, l1, l8 and I9 in intersecting these cooling passages. The middle part 6, however, is in this construction bored from both sides 6, 6" in such a way that the axes of all passages on each side of the middle plane 2| lie each on a hyperboloid of revolution of one sheet, so that the distance of 3 4 the bores from the cylinder axis is smallest outgreater than in the zones in which the piston side the cylinder middle plane 2|, and increases rings are situated when the pistons are in their again towards the middle plane. Each part pasinner dead center. sage bored from one side of the strengthened mid- 4. A cylinder liner as claimed in claim 1, the

dle part 5 intersects a similar part passage bored 5 diameter of the inner surface of which in the fromthe othergside in the cylinder middle plane middle rpart not swept bystlie piston rings is 2| thus together forming by couples |2l3, smaller than the diameter of the inner surface of I l-4 5, lfie-l l and l8l9, for example, a continthe remaining part of the liner. uous passage for the cooling-medium. 5. A cylinder liner for opposed piston internal Through this arrangement ery effective-moors; lo xcombustionrengines having a strengthened middle ing is obtained of the zone in which the piston -.part surrounding the combustion chamber, a plurings 23 are at their inner, dead centre. vAlso rality of passages in said middle part oblique to here the run of the cylinderinnenwall Zflydevithe axis of thecylinder for the circulation of a ates from the straight in the middle zone and coolingmedium'said passages being so arranged follows approximately the run of the cooling- 15 that their ax'es belong to the generating lines of bores, whereby the heat stresses in thecylin-dr -asinglesidedhyperboloid of revolution and that wall are diminished. '--tl1eir-==distance from the cylinder axis decreases to In the embodiment shown in Fig. 4, the .a-minimum in substantially the middle sectional strengthened middlepart 6 is also bored from the plane of the cylinder liner, the inner surface of two sidesfi andlif', but here the axes ofthe bores 20 .said middle, part being shaped as a single-sided each lie on'a circular cone? ,Related bores; such hyperboloi'd of'revolution so that-the wall thicklas 25,and' 26 intersect in the middle plane of the i'ness between the rc'ooling passages and'the inner cylinderij; By reducing the internal diameter of surface of'thelineris at-least-approximately'con- "1. hj l ylinder in the; middle zone the efiect'obtained stant. s.similar to;that described in the case of Fig. 2. '5 6. Acylinderliner-for opposed piston" internal Through .the invention better cooling is obcombustionrengineshaving-a"strengthened mid- ."gtained of the runningasurfaces or of the pistons die part surrounding-the combustion chamber, a for internal combustion engines. ""fjPlllIfilil'iY ofangular-passages in said-middle part Iclaim: for the circulation Of'a: coolingmedium; each of l. Acylinder liner for opposed pistoninternm saidpassageshaving'awertex at' substantially-the gcombustionflengines having a strengthened midr middle'sectional' plane of the cylinder-,-the-wall j? dlepartsurrounding the combustion chamber, a thickness between said passagesand theinner plurality of passages in saidmi'ddle part. oblique surface of-thediner in'the middle partner-sw pt to.,the axis of the cylinder for thecirculation' of r-by'the-pi 0 rings-being atleast ap r imately a. cooling medium1the inner surface of said ga constant. I

1.Istlien thenedjmiddle part of the liner not swept v HANS STEINER. ,3 b the piston rings deviatin .from, the j-cylindrical .vlsham M g V oREFERENGES' i-CITED V '3' 2. A 'cylindenliner. asolaimed in claim Lthe 1,The.iollowingreierences,are oLrec-orcl in the wall thickness' Of which between the .Q II v Das- 44) m of t at t; saees and the :innersurfaQe deviating from the cylindrical shape is approximately constant. "Nimn S QPATEN'TS 3. lycylinder liner as claimed, inclaim 1,.-the Number Name Date wall'thickness of ,which between the coolingpas- ;1;4'10,319 Junkers Mar. 21', 1922 sages and the innersuriac'e deviatingfrom. the" "2,193,884 vRetschy ".Mar;,19',1'940 f.cylindrical shape is a'tleast in. someplaces, "2,'2 i4;323 -Antonsen et al. June 3,1941 

